Screen printer

ABSTRACT

A screen printer capable of concurrently, efficiently subjecting a plurality of different types of substrates, to a printing operation. The screen printer makes up an electronic component mounting line and prints electronic component bonding paste on a substrate. A substrate conveyance section that conveys a substrate forwardly or backwardly in a direction of conveyance of a substrate is disposed at an intermediate position between a first screen printing section and a second screen printing section arranged symmetrically with respect to a center line CL. It thereby becomes possible to adopt a variety of substrate conveyance forms, as required, such as return conveyance for returning the substrate from a downstream machine to an upstream side of the screen printer and bypass conveyance for letting the substrate sent from an upstream side pass through the screen printer, to thus be conveyed to a downstream machine.

TECHNICAL FIELD

The present invention relates to a screen printer that makes up anelectronic component mounting line, which manufactures a mountedsubstrate by mounting electronic components on a substrate and thatprints solder bonding paste on the substrate.

BACKGROUND ART

An electronic component mounting line through which a mounted substrateis manufactured by mounting electronic components on a substrate isconstructed by coupling together screen printers that print solderbonding paste on electronic components, electronic component loaders forloading the electronic components on a printed substrate, and the like.Producing multiple products in small quantities has recently become apredominant production style in the electronic industry, too. Therefore,a production facility has also become required to have a facilityconfiguration that exhibits both the ability to achieve high productionefficiency and flexibility to adapt to a variety of production styles.

In order to realize such a production facility, various characteristicmechanisms and configurations have hitherto been brought into a layoutof an electronic component mounting line and machines constituting theelectronic component mounting line. For instance, a configurationincluding a plurality of independently movable substrate transportconveyors (see Patent Document 1) is used for the purpose of enhancingtransport efficiency of substrates and simultaneous transport of aplurality of substrates. Simultaneous production of a plurality ofsubstrate thereby becomes possible, to thus achieve superior productionefficiency. Further, a facility that has the superior capability ofaddressing production of multiple products and that enables simultaneousproduction of a plurality of types of substrates can be implemented.

In order to simultaneously produce a plurality of substrates, a screenprinter's throughput capacity to feed solder bonding paste to asubstrate must be increased so as to meet the number of substrates to beproduced. For this reason, there have been employed various mechanisms,such as a configuration for arranging a plurality of screen printers inseries along an electronic component mounting line, to thus increaseoverall throughput capacity (see Patent Document 2), a method forincreasing the number of substrates to be processed by simultaneouslyprinting two substrates by means of a single mask plate (see PatentDocument 3), and a method for increasing the number of substrates to beprocessed by arranging independent screen printing mechanisms in serieswithin a single system.

-   Patent Document 1: JP-A-4-129630-   Patent Document 2: JP-A-2004-142299-   Patent Document 3: JP-A-2000-37847-   Patent Document 4: JP-A-2000-168040

DISCLOSURE OF THE INVENTION Problem that the Invention is to Solve

However, the example related-art technologies described in connectionwith Patent Documents 2 and 3 suffer problems, such as those providedbelow. Specifically, all of the example technologies described inconnection with Patent Documents 2 and 3 adopt a configuration forconveying a substrate by means of a single substrate conveyance path.Therefore, a substrate conveyance sequence along which a printedsubstrate is delivered to a downstream electronic component loader isfixed, and difficulty is encountered in supplying a substrate requiredfor the downstream machine at required timing. For this reason, it hasbeen difficult to apply the configurations described in connection withthe example related-art technologies to mixed-flow production involvingsimultaneous flow of different types of substrates.

A two-sided mount style for mounting electronic components on both sidesof a substrate has recently become common practice on account of anincrease in packing density. For this reason, there is needed substrateconveyance operation for returning the substrate, one side of which hasfinished undergoing mounting operation, to an upstream position withrespect to the screen printer. However, in a related-art screen printer,such an operation for conveying a substrate is manually performed by aworker in many cases. Implementing laborsaving by full automatization ofsubstrate conveyance operation has been longed. As mentioned above, thescreen printers employed in the related-art electronic componentmounting line suffer a problem of the difficulty of concurrently,efficiently subjecting a plurality of substrates, including differenttypes of substrates, to printing operation.

The present invention aims at providing a screen printer capable ofconcurrently, efficiently performing printing operation on a pluralityof substrates including different types of substrates.

Means for Solving the Problem

The present invention provides a screen printer that is coupled to anupstream side of an electronic component loader which mounts electroniccomponents on a substrate, to thus make up an electronic componentmounting line, and that prints electronic component bonding paste to thesubstrate, the printer comprising: two screen printing sections thateach have a mask plate including a pattern hole and a squeegee movingmechanism which lets a squeegee slidably move over the mask platesupplied with paste and that are arranged symmetrically with respect toa center line of the electronic component mounting line when viewed inplane; a substrate positioning section that is provided in each of thetwo screen printing sections and that positions and holds the substrateat a print position for the screen printing section of interest; and asubstrate conveyance section that is disposed between the two screenprinting sections and that conveys the substrate in a direction ofconveyance of a substrate.

Advantage of the Invention

In the screen printer of the present invention, the substrate conveyancesection that conveys the substrate in the direction of conveyance of asubstrate is disposed at an intermediate position between two screenprinting sections that are arranged symmetrically with respect to acenter line. It thereby becomes possible to adopt a variety of substrateconveyance forms, as required, such as return conveyance for returningthe substrate from a downstream machine to an upstream side of thescreen printer and bypass conveyance for letting the substrate sent fromthe upstream side pass through the screen printer, to thus be conveyedto a downstream machine. The plurality of substrates, includingdifferent types of substrates, can concurrently, efficiently undergoprinting operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a configuration of an electronic componentmounting line of a first embodiment of the present invention.

FIG. 2 is a plan view showing a screen printer of the first embodimentof the present invention.

FIG. 3 is a cross-sectional view of the screen printer of the firstembodiment of the present invention.

FIG. 4 is a cross-sectional view of a screen printing section in thescreen printer of the first embodiment of the present invention.

FIG. 5 is a descriptive operation diagram of substrate conveyance motionof the screen printer of the first embodiment of the present invention.

FIG. 6 is a descriptive operation diagram of substrate conveyance motionof the screen printer of the first embodiment of the present invention.

FIG. 7 is a plan view showing a configuration of an electronic componentmounting line of a second embodiment of the present invention.

FIG. 8 is a plan view showing a screen printer of the second embodimentof the present invention.

FIG. 9 is a cross-sectional view of the screen printer of the secondembodiment of the present invention.

FIG. 10 is a descriptive operation diagram of substrate conveyancemotion performed by the screen printer of the second embodiment of thepresent invention.

FIG. 11 is a descriptive operation diagram of substrate conveyancemotion performed by the screen printer of the second embodiment of thepresent invention.

FIG. 12 is a descriptive operation diagram of substrate conveyancemotion performed by the screen printer of the second embodiment of thepresent invention.

FIG. 13 is a plan view showing a configuration of an electroniccomponent mounting line of a third embodiment of the present invention.

FIG. 14 is a descriptive operation diagram of substrate conveyancemotion of a screen printer of the third embodiment of the presentinvention.

FIG. 15 is a descriptive operation diagram of substrate conveyancemotion of the screen printer of the third embodiment of the presentinvention.

FIG. 16 is a descriptive operation diagram of substrate conveyancemotion of the screen printer of the third embodiment of the presentinvention.

DESCRIPTIONS OF THE REFERENCE NUMERALS AND SYMBOLS

-   -   1, 1A, 1B ELECTRONIC COMPONENT MOUNTING LINE    -   2, 2A PRINTER (SCREEN PRINTER)    -   3, 3A, 3B LOADER (ELECTRONIC COMPONENT LOADER)    -   4, 4A SUBSTRATE SORTER    -   5, 5A, 5B, 5C, 5D SUBSTRATE    -   7A FIRST SCREEN PRINTING SECTION    -   7B SECOND SCREEN PRINTING SECTION    -   8, 8A SUBSTRATE CONVEYANCE SECTION    -   8 b SUBSTRATE CONVEYANCE RAIL    -   12A, 12B, 12C SUBSTRATE CONVEYANCE RAIL    -   21 SUBSTRATE POSITIONING SECTION    -   32 MASK PLATE    -   33 SQUEEGEE UNIT    -   36 SQUEEGEE    -   L1, L2, L3, L4 SUBSTRATE CONVEYANCE LANE

BEST MODES FOR IMPLEMENTING THE INVENTION

Embodiments of the present invention are described hereunder byreference to the drawings.

First Embodiment

FIG. 1 is a plan view showing a configuration of an electronic componentmounting line of a first embodiment of the present invention; FIG. 2 isa plan view showing a screen printer of the first embodiment of thepresent invention; FIG. 3 is a cross-sectional view of the screenprinter of the first embodiment of the present invention; FIG. 4 is across-sectional view of a screen printing section in the screen printerof the first embodiment of the present invention; FIG. 5 is adescriptive operation diagram of substrate conveyance motion of thescreen printer of the first embodiment of the present invention; andFIG. 6 is a descriptive operation diagram of substrate conveyance motionof the screen printer of the first embodiment of the present invention.

A configuration of an electronic component mounting line 1 is firstdescribed by reference to FIG. 1. The electronic component mounting line1 has a function of manufacturing a mounted substrate by mountingelectronic components on a substrate and is also configured such that ascreen printer 2 (hereinafter abbreviated simply as a “printer 2”) thatprints electronic component bonding paste on a substrate is coupled toan upstream side (on a left-hand side in FIG. 1) of an electroniccomponent loader 3 (hereinafter abbreviated simply as a “loader 3”) thatmounts electronic components on a substrate. In descriptions of thepresent specification, subscripts (1), (2), . . . assigned to respectivemachines, such as a printer and a loader, designate a sequence ofarrangement of the machines in the electronic component mounting linefrom the upstream side.

In the present embodiment, two loaders 3(1) and 3(2) are coupled inseries to a downstream side of one printer 2. A substrate sorter 4(1) isannexed to an upstream side of the printer 2, and a substrate sorter4(2) is annexed to a downstream side of the printer 2. A substratecarried out of an upstream apparatus is brought into the printer 2 byway of the substrate sorter 4(1). The substrate that has undergonescreen printing in the printer 2 is delivered to the loader 3(1) by wayof the substrate sorter 4(2).

The printer 2 is made up of first and second screen printing sections 7Aand 7B, each of which has a function of printing electronic componentbonding paste on a substrate 5 which is to serve as an object ofmounting operation, wherein the first and second screen printingsections are arranged on a common base 6 so as to become symmetricalabout a line center CL of the electronic component line 1 when viewed inplane. A substrate conveyance section 8 that forwardly or backwardlyconveys the substrate 5 in a substrate conveyance direction (a directionX) is disposed at an intermediate position between the first screenprinting section 7A and the second screen printing section 7B.

A configuration of the loader 3 is now described. The loader 3(1) andthe loader 3(2) are structurally identical with each other. Explanationsare given solely to the loader 3(1) by assigning reference numerals toindividual constituent elements. Three pairs of substrate conveyancerails 12A, 12B, and 12C are laid in parallel to each other at the centerof a base 11 along a direction of conveyance of a substrate (the Xdirection). The substrate conveyance rails 12A, 12B, and 12C make upthree rows of substrate conveyance lanes L1, L2, and L3 that convey thesubstrate 5 passed from the printer 2 by way of the substrate sorter4(2), respectively. In the present embodiment, each of only thesubstrate conveyance lanes L1 and L3, among the three rows of substrateconveyance lanes L1, L2, and L3, is provided with a mount stage forpositioning the substrate 5 at a mounting position and performingmounting operation. The substrate conveyance lane L2 located at thecenter is designed so as to act as a return conveyance path forconveying the substrate 5 from the downstream side to the upstream side.

A component feeding section 13A is disposed on the outside of thesubstrate conveyance rail 12A, and a component feeding section 13B isdisposed on the outside of the substrate conveyance rail 12B. Aplurality of tape feeders 14 are arranged side by side in each of thecomponent feeding sections 13A and 13B. The tape feeder 14 performspitch feed of a carrier tape holding electronic components to be mountedon the substrate 5, thereby supplying an electronic component to acomponent pickup position by means of a component loading mechanism tobe described below. A Y-axis moving table 15 is disposed on anX-direction end of the base 11. Two X-axis moving tables 16A and 16Bcoupled to the Y-axis moving table 15 are equipped with loading heads17A and 17B, respectively. Each of the loading heads 17A and 17B isequipped with a plurality of unit loading heads, and an electroniccomponent is held by a suction nozzle provided on the individual unitloading head by means of vacuum suction.

The loading heads 17A and 17B are horizontally moved in both the Xdirection and the Y direction, by driving the Y-axis moving table 15 andthe X-axis moving tables 16A and 16B. The loading heads 17A and 17B pickup electronic components from the tape feeders 14 of the respectivecomponent feeding sections 13A and 13B by means of suction and transferand mount the thus-picked-up electronic components to the substrates 5positioned on the respective mount stages of the substrate conveyancerails 12A and 12B. Component recognition cameras 18A and 18B are placedat any positions along respective travel paths of the loading heads 17Aand 17B. When the loading heads 17A and 17B holding the electroniccomponents travel over the component recognition cameras 18A and 18B,whereby the component recognition cameras 18A and 18B capture, frombelow, images of the electronic components held by the loading heads 17Aand 17B, thereby determining the electronic components throughrecognition.

By reference to FIGS. 2, 3, and 4, a structure of the printer 2 is nowdescribed. FIG. 3 shows a cross section of the printer when viewed in anarrowy direction A-A shown in FIG. 2, and FIG. 4 is a detailed crosssectional view for describing a structure of the first screen printingsection 7A and a structure of the second screen printing section 7B. Asindicated by the cross section shown in FIG. 3, the printer 2 hassubstrate positioning sections 21 that each are provided in the firstscreen printing section 7A and the second screen printing section 7B,which are arranged on the base 6 in a symmetrical pattern, for holdingthe substrates 5 at respective print positions. A mask plate 32 havingpattern holes and a squeegee moving mechanism 37 that slidably moves asqueegee 36 (see FIG. 4) of a squeegee unit 33 over the mask plate 32supplied with paste are arranged above the substrate positioning section21. The mask plate 32, the squeegee unit 33, and the squeegee movingmechanism 37 make up a screen printing mechanism that prints paste onthe substrate 5 of interest.

A detailed configuration of the substrate positioning section 21, adetailed configuration of the squeegee unit 33, and a detailedconfiguration of the squeegee moving mechanism 37 are described byreference to FIG. 4. In FIG. 4, the substrate positioning section 21 isbuilt by stacking a Y-axis table 22, an X-axis table 23, and a O-axistable 24 into layers and by additional stacking of a first Z-axis table25 and a second Z-axis table 26 on these tables in combination. Aconfiguration of the first Z-axis table 25 is described. A horizontalbase plate 24 a is provided on an upper surface of the O-axis table 24,and a horizontal base plate 25 a is likewise held on the upper surfaceside of the base plate 24 a by an elevation guide mechanism (not shown)so as to freely ascend or descend. The base plate 25 a is caused toascend or descend by a Z-axis elevation mechanism constructed so as torotationally drive a plurality of feed screws 25 c by way of a belt 25 dby means of a substrate moving Z-axis motor 25 b. Two vertical frames 25e stand upright on the base plate 25 a, and a pair of substrateconveyance rails 28 making up a substrate conveyance path are held onupper ends of the respective vertical frames 25 e.

The substrate conveyance rails 28 are laid in parallel to the directionof conveyance of a substrate (the X direction; in other words, adirection perpendicular to a drawing sheet of FIG. 1). The substrate 5that is an object of printing is conveyed while both ends of thesubstrate are supported by a conveyor mechanism provided on thesubstrate conveyance rails 28. The substrate 5 held by the substrateconveyance rails 28 can be caused to ascend or descend with respect tothe screen printing mechanism in conjunction with the substrateconveyance rails 28 by driving the first Z-axis table 25.

A configuration of the second Z-axis table 26 is described. A horizontalbase plate 26 a is interposed between the conveyance rails 28 and thebase plate 25 a so as to be able to freely ascend or descend along theelevation guide mechanism (omitted from the drawings). The base plate 26a is caused to ascend or descend by means of the Z-axis elevationmechanism configured so as to rotationally drive a plurality of feedscrews 26 c by means of a lower support elevation motor 26 b and by wayof a belt 26 d. A substrate support section 27 is removably attached tothe upper surface of the base plate 26 a. The substrate support section27 supports from below the substrate 5 conveyed to the print position bymeans of the screen printing mechanism.

In printing operation of the first screen printing section 7A and thesecond screen printing section 7B, the substrate conveyance rails 28receive the respective substrates 5 fed from an upstream machine by wayof sorting conveyors 41A and 41B of the substrate sorter 4(1); conveythe thus-received substrates to the respective print positions for thescreen printing mechanisms; and hold the substrates at the positions.The substrate conveyance rails 28 carry the substrates 5, which haveundergone printing in the screen printing mechanisms, out of the printpositions and send the thus-carried substrates to sorting conveyors 42Aand 42B of the substrate sorter 4(2).

The substrate support section 27 ascends or descends with respect to thesubstrate 5 held by the substrate conveyance rails 28 by actuation ofthe second Z-axis table 26. A lower support surface of the substratesupport section 27 comes into contact with the lower surface of thesubstrate 5, whereby the substrate support section 27 supports thesubstrate 5 from its lower surface side. A clamp mechanism 29 isdisposed on upper surfaces of the substrate conveyance rails 28. Theclamp mechanism 29 has two clamp members 29 a positioned side by side soas to oppose each other. A drive mechanism 29 b lets one clamp member 29a move forward or backward, thereby clamping and fastening the substrate5 from both sides thereof.

An explanation is now given to a structure of the screen print mechanismthat is disposed above the substrate positioning section 21 and thatprints paste on the substrate conveyed to the print position. In FIGS. 2and 4, the mask plate 32 is extended over a mask frame 31 held by a maskholder (omitted from the drawing). A pattern hole 32 a is provided, inthe mask plate 32, at a position corresponding to a print area on thesubstrate 5. The squeegee unit 33 is disposed on the mask plate 32 so asto be movable by means of the squeegee moving mechanism 37.

The squeegee unit 33 is configured such that two squeegee elevationmechanisms 35 for elevating or lowering the pair of mutually-opposedsqueegees 36 are disposed on a horizontal moving plate 34. The squeegeemoving mechanism 37, in which a feed screw 37 b to be rotationallydriven by a squeegee moving motor 37 is screw-engaged with a nut member37 c secured on a lower surface of the moving plate 34 horizontally,moves the squeegee unit 33 forward and backward along the direction Y.The mask plate 32, the moving plate 34, and the squeegee movingmechanism 37, and the like, of the first screen printing section 7A,among the first screen printing section 7A and the second screenprinting section 7B, are omitted from FIG. 2.

As shown in FIG. 2, a head X-axis table 40X that is actuated in the Ydirection by means of a head Y-axis table 40Y is disposed at an elevatedposition above the substrate positioning section 21. The head X-axistable 40X is equipped with a camera head unit 38 and a mask cleaningunit 39. Further, the camera head unit 38 is equipped with a substraterecognition camera 38 a for capturing an image of the substrate 5 fromabove and a mask recognition camera 38 b for capturing an image of themask plate 32 from its lower surface. The mask cleaning unit 39 has acleaning head for cleaning a lower surface of the mask plate 32.

The camera head unit 38 and the mask cleaning unit 39 are horizontallymoved by actuating the head X-axis table 40× and the head Y-axis table40Y, whereby recognition of the substrate 5 and recognition of the maskplate 32 can simultaneously be carried out. When necessary, the lowersurface of the mask plate 32 can be cleaned. When these operations arenot performed, the camera head unit 38 and the mask cleaning unit 39remain situated at positions that are receded sideways from elevatedpositions above the substrate positioning section 21.

Printing operation of the first screen printing section 7A and printingoperation of the second screen printing operation 7B are now described.First, the substrate conveyance rails 28 carry the substrate 5 to beprinted into the print position, where the substrate is positioned withrespect to the substrate support section 27. Next, the second Z-axistable 27 is caused to ascend by actuation of the second Z-axis table 26,thereby supporting a lower surface of the substrate 5. The substratepositioning section 21 is then actuated, to thus position the substrate5 with respect to the mask plate 32. Subsequently, the first Z-axistable 25 is actuated, to thus elevate the substrate 5 along with thesubstrate conveyance rails 28 so as to contact the lower surface of themask plate 32 having the pattern hole 32 a.

Subsequently, the clamp mechanism 29 clamps the substrate 5, whereby ahorizontal position of the substrate 5 is fixed. One of the twosqueegees 36 is lowered in this state so as to come into contact withthe mask plate 32. Next, the squeegee 36 is caused to slide over themask plate 32 supplied with paste, such as cream solder, in a squeezingdirection (the Y direction), whereby the paste is printed on thesubstrate 5 by way of the pattern hole 32 a.

As shown in FIGS. 2 and 3, the substrate conveyance section 8 isdisposed, on the upper surface of the base 6, at an intermediateposition between the first screen printing section 7A and the secondscreen printing section 7B along the center line CL and in the Xdirection. The substrate conveyance section 8 is configured such thatsubstrate conveyance rails 8 b equipped with a conveyor mechanism forthe purpose of conveying a substrate are held on upper ends ofrespective frames 8 a set upright on the base 6, so that the substrate 5can be carried in both forward and backward directions by means of thesubstrate conveyance rails 8 b.

Specifically, the conveyor mechanism of the substrate conveyance rails 8b is moved toward the downstream side, whereby the substrate 5 suppliedfrom an upstream machine can be sent to a downstream machine by means ofbypassing the first screen printing section 7A and the second screenprinting section 7B. In this case, the substrate conveyance section 8functions as a conveyance bypass for letting the substrate 5 deliveredto the downstream machine pass. Further, the conveyor mechanism of thesubstrate conveyance rails 8 b are actuated in an upstream direction,whereby the substrate 5 returned from the downstream machine can bereturned to the upstream side of the printer 2. In this case, thesubstrate conveyance section 8 acts as a return conveyance path forconveying the substrate that returns from the downstream side of theelectronic component mounting line 1 to the upstream side of the screenprinter 2.

The substrate sorter 4(1) disposed on the upstream side of the printer 2has sorting conveyors 41A, 41B, and 41C, each of which has a conveyormechanism for conveying a substrate, and the substrate sorter 4(2)adjacently disposed on the downstream side of the printer 2 has sortingconveyors 42A, 42B, and 42C. The sorting conveyors 41A, 41B, 41C, 42A,42B, and 42C are individually movable in the Y direction (see arrows a1,a2, a3, b1, b2, and b3) by means of respective conveyance rail movingmechanisms (omitted from the drawing).

By means of movement of the sorting conveyors in the Y direction, thesubstrate sorter 4(1) can couple the sorting conveyors 41A and 41B,which usually remain coupled to the substrate conveyance rails 28 of thefirst screen printing section 7A and the second screen printing section7B, to the substrate conveyance rails 8 b of the substrate conveyancesection 8, as required. At this time, the sorting conveyor 41B recedesfrom the position where the conveyor is coupled to the correspondingsubstrate conveyance rails 8 b. Moreover, in normal times, the sortingconveyor 41B coupled to the substrate conveyance section 8 can becoupled to the substrate conveyance rails 28 of the first screenprinting section 7A and the substrate conveyance rails 28 of the secondscreen printing section 7B, as required. At this time, the sortingconveyors 41A and 41B recede from the positions where the conveyors arecoupled to their corresponding substrate conveyance rails 28.

Moreover, in the substrate sorter 4(2), the sorting conveyors 42A and42B coupled to the substrate conveyance rails 28 of the first screenprinting section 7A and the substrate conveyance rails 28 of the secondscreen printing section 7B in normal times can be coupled to theircorresponding substrate conveyance rails 12A and 12B of the loader 3(1),as necessary. The printed substrates 5 can be sent from the substratepositioning section 21 of the first screen printing section 7A and thesubstrate positioning section 21 of the second screen printing section7B to the loader 3(1) that is a downstream machine.

Substrate conveyance operation of the printer 2 is now described byreference to FIGS. 5 and 6. The substrate 5 serving as an object ofmounting is herein a two-sided mount substrate on both sides of whichelectronic components are to be mounted. There is illustrated exampleoperation performed when the substrate conveyance section 8 is used as areturn conveyance path for returning a substrate 5*, which has finishedundergoing operation for mounting components on a lower surface of thesubstrate, to the upstream side of the printer 2 of interest.Specifically, as shown in FIG. 5, operation for printing paste on afirst side (an upper surface) that first undergoes mounting operation iscarried out by the screen printing section on one side of the printer 2(the first screen printing section 7A in the embodiment). Therefore, anew substrate 5 that has not yet undergone printing operation is carriedinto the sorting conveyor 41A coupled to the substrate conveyance rails28 of the first screen printing section 7A (as designated by an arrow“c”).

The substrate 5 is sent from the sorting conveyor 41A to the substratepositioning section 21 of the first screen printing section 7A (asdesignated by an arrow “d”), where the screen printing mechanism of thefirst screen printing section 7A performs printing operation. Thesubstrate 5 having undergone printing operation is sent to the sortingconveyor 42A of the substrate sorter 4(2) (as designated by an arrow“e”). Next, the sorting conveyor 42A moves in the Y direction, to thusbecome coupled to the substrate conveyance rails 12A of the loader 3(1),whereby the substrate 5 is sent to the substrate conveyance lane L1 ofthe loader 3(1) (see FIG. 1). The substrate 5 moves to the downstreamside along the substrate conveyance lane L1, whereby the loader 3(1) andthe loader 3(2) subject the substrate 5 having undergone printingoperation to predetermined component mounting operation intended for thefirst side.

Subsequently, the substrate 5 having undergone component loadingoperation is sent further to a downstream reflow machine (omitted fromthe drawing), to thus undergo processing relating to a predeterminedreflow process, with the result that the component mounting operationintended for the upper surface of the substrate 5 is completed. Asmentioned above, the substrate 5 having finished undergoing operationfor mounting electronic components on an upper surface is conveyed inthe direction of the upstream side while turned inside out and while itslower surface, which is a second surface side, is directed upward (thesubstrate remaining in this attitude is written as a substrate 5* so asto be distinguished from the substrate 5 whose upper surface is directedupward) by way of the substrate conveyance lane L2 of the loader 3(1)and the loader 3(2). The substrate 5* is sent to the sorting conveyor42C of the substrate sorter 4(2) (as designated by an arrow “f”).Further, the substrate is sent from the sorting conveyor 42C to thesubstrate conveyance rails 8 b of the substrate conveyance section 8 (asdesignated by an arrow “g”). The substrate 5* conveyed by the substrateconveyance section 8 up to the upstream side of the printer 2 undergoesprinting operation intended for a lower surface; hence, the substratesorter 4(1) shifts the substrate toward the second screen printingsection 7B.

Shift-conveyance of the substrate 5* may also be performed according toa method (as designated by an arrow “h”) for conveying the substrate 5*,which has been sent from the substrate conveyance section 8 to thesorting conveyor 41C, to the sorting conveyor 41B by manpower ortransporting the same by means of a transfer machine. Moreover,shift-conveyance of the substrate 5* may also be performed by slidingthe sorting conveyor 41C or the sorting conveyor 41B in the Y direction.

Specifically, the sorting conveyor 41C received the substrate 5* fromthe substrate conveyance section 8 may also be moved toward the secondscreen printing section 7B, to thus become coupled to the substrateconveyance rails 28, thereby sending the substrate 5* to the secondscreen printing section 7B. Alternatively, the sorting conveyor 41Bmoved toward the substrate conveyance section 8 may also receive thesubstrate 5*, and the sorting conveyor 41 returned to the second screenprinting section 7B may be coupled to the substrate conveyance rails 28,thereby sending the substrate 5* to the second screen printing section7B.

Subsequently, the substrate 5* is sent to the substrate positioningsection 21 of the second screen printing section 7B (as designated by anarrow “i”), where the substrate undergoes printing operation performedby the second screen printing section 7B. The substrate 5* havingundergone printing operation is sent to the sorting conveyor 42B of thesubstrate sorter 4(2) (as designated by an arrow “j”). The sortingconveyor 42B then moves in the Y direction, to thus become coupled tothe substrate conveyance rails 12B of the loader 3(1), whereby thesubstrate 5* is sent to the substrate conveyance lane L3 of the loader3(1) (see FIG. 1). As a result of the substrate 5* moving to thedownstream side along the substrate conveyance lane L3, the loader 3(1)and the loader 3(2) subject the substrate 5* having undergone printingoperation to predetermined component loading operation intended for alower surface.

FIG. 6 shows substrate conveyance operation that is performed in a statewhere the electronic component mounting operation intended for atwo-sided mounted substrate by the electronic component mounting line 1is steadily performed. Specifically, in the first screen printingsection 7A, the substrate 5 is sent from the sorting conveyor 41A to thesubstrate conveyance rails 28, and the substrate positioning section 21positions the substrate. The substrate 5 in this state is subjected toprinting operation performed by the first screen printing section 7A.The substrate 5 having finished undergoing printing operation isdelivered to a downstream machine by way of the sorting conveyor 42A.Further, the substrate conveyance section 8 performs substrate returnconveyance operation for conveying the substrate 5*, which has beenreturned from the downstream machine by way of the sorting conveyor 42C,to the upstream side and sending the substrate to the sorting conveyor41C.

Further, in the second screen printing section 7B, the substrate 5*shifted and conveyed from the substrate conveyance section 8 is againcharged into the substrate positioning section 21 by way of thesubstrate conveyance rails 28. The substrate 5* then undergoes printingoperation performed by the second screen printing section 7B. Thesubstrate 5 having undergone printing operation is sent to a downstreammachine by way of the sorting conveyor 42B. In the configuration, thesubstrate sorter 4(1) acts as a substrate recharge section that againcharges the substrate 5*, which has been returned to the upstream sideof a corresponding screen printer by the substrate conveyance section 8acting as the return conveyance path, into the substrate positioningsection 21 of the printer 2. The substrate sorter 4(2) acts as asubstrate delivering/receiving section that delivers and receives thesubstrate 5 between the substrate positioning section 21 of the printer2 or the substrate conveyance section 8 and the loader 3 that is adownstream machine situated on the downstream side of the printer 2.

Second Embodiment

FIG. 7 is a plan view showing a configuration of an electronic componentmounting line of a second embodiment of the present invention. FIG. 8 isa plan view showing a screen printer of the second embodiment of thepresent invention. FIG. 9 is a cross-sectional view of the screenprinter of the second embodiment of the present invention. FIG. 10, FIG.11, and FIG. 12 are descriptive operation diagrams of substrateconveyance motion of the screen printer of the second embodiment of thepresent invention.

First, a configuration of an electronic component mounting line 1A isdescribed by reference to FIG. 7. The electronic component mounting line1A has a function of manufacturing a mounted substrate by mountingelectronic components on a substrate, as does the electronic componentmounting line 1 described in connection with the first embodiment; andis configured such that printers 2A that each print electronic componentbonding paste on a substrate are coupled to an upstream side of anelectronic component loader 3A that mounts electronic components on asubstrate. In the second embodiment, respective downstream sides of thetwo printers 2A arranged in series are coupled to two loaders 3A(1) and3A(2) similarly arranged in series.

In order to deliver and receive the substrate among the machines, asubstrate sorter 4A(1) is adjacently disposed at an upstream side of aprinter 2A(1); a substrate sorter 4A(2) is adjacently disposed betweenthe printer 2A(1) and a printer 2A(2); and a substrate sorter 4A(3) isadjacently disposed on a downstream side of the printer 2A(2).Specifically, the substrate carried out of the upstream machine iscarried into the printer 2A(1) by way of the substrate sorter 4A(1) andfurther into the printer 2A(2) by way of the substrate sorter 4A(2). Thesubstrate having undergone printing operation performed by the printer2A(1) or the printer 2A(2) is delivered to the loader 3(1) by way of thesubstrate sorter 4A(3).

The printer 2A is configured in such a way that a first screen printingsection 7A and a second screen printing section 7B, which are analogousto their counterparts describe in connection with the first embodimentin terms of a configuration and a function, are symmetrically arrangedon the common base 6 with respect to the center line CL of theelectronic component mounting line 1 when viewed in plane. A substrateconveyance section 8A that conveys the substrate 5 forwardly orbackwardly along the direction of conveyance of a substrate (i.e., the Xdirection) is disposed between the first screen printing section 7A andthe second screen printing section 7B.

As shown in FIGS. 8 and 9, the substrate conveyance section 8A isconfigured in such a way that two rows of substrate conveyance rails 8b, which each have a conveyance mechanism for the purpose of conveying asubstrate, are adjacently provided side by side on upper ends of frames8 a disposed upright on the base 6. The printer 2A is configured so asto have two substrate conveyance lanes L1 and L2 that convey thesubstrate 5 in the direction of conveyance of a substrate (the Xdirection). Specifically, in the second embodiment, the substrateconveyance section 8 is configured so as to have a plurality ofsubstrate conveyance lanes (substrate conveyance paths) for conveyingthe substrate 5. As will be described later, the plurality of substrateconveyance lanes assume a form including a conveyance bypass for lettinga substrate sent to a downstream machine pass through.

The substrate sorters 4A(1) to 4A(3) assume an identical configuration.As shown in FIG. 8, the substrate sorters 4A(1) to 4A(3) are configuredsuch that the substrate sorting conveyors (the sorting conveyors 41C and42C) located at the center are omitted from the configuration of thesubstrate sorter 4 described in connection with the first embodiment.Specifically, the substrate sorter 4A(1) has sorting conveyors 41A and41B; the substrate sorter 4A(2) has sorting conveyors 42A and 42B; andthe substrate sorter 4A(3) has sorting conveyors 43A and 43B. Thesubstrate sorting conveyors are arranged so as to be movable in the Ydirection.

A configuration of the loader 3A is now described. The loader 3A(1) andthe loader 3A(2) are structurally identical with each other. The loader3A is different from the loader 3 described in connection with the firstembodiment in connection with the configuration of the substrateconveyance path laid in the center along the direction of conveyance ofa substrate (the X direction). In other respects, the loader 3A has thesame configuration as that of the loader 3. Specifically, the two pairsof substrate conveyance rails 12A and 12B are laid in parallel to eachother in the loader 3A. The substrate conveyance rails 12A and 12B makeup the respective substrate conveyance lanes L1 and L2 that convey thesubstrates 5 sent from the upstream side by way of the substrate sorter4A(3).

In the substrate sorter 4A(3), by means of movement of the sortingconveyors 43A and 43B the substrates 5 can be delivered or receivedbetween the substrate conveyance lanes L1 and L2 of the loader 3A(1) andthe substrate conveyance lanes L1 and L2 of the printer 2A(2) by way ofthe sorting conveyors 43A and 43B. Likewise, by means of movement of thesorting conveyors 43A and 43B the respective substrate positioningsections 21 of the first screen printing section 7A and the secondscreen printing section 7B in the printer 2A(2) can deliver thesubstrates 5 to the substrate conveyance lanes L1 and L2 of the loader3A(1). Each of the substrate conveyance lanes L1 and L2 has a mountingstage for performing mounting operation while positioning the substrate5 at the mounting position. The substrate 5 positioned on the mountingstage is subjected to operation for transferring and mounting electroniccomponents, by means of the component loading mechanisms analogous tothe loader 3 described in connection with the first embodiment.

By reference to FIGS. 10, 11, and 12, substrate conveyance operation ofthe printer 2A is now descried. There is illustrated example substrateconveyance operation performed when two different types of substrates 5(a substrate 5A and a substrate 5B) are concurrently subjected toprinting operation. FIG. 10 shows general work classification effectedwhen the two printers 2A(1) and 2A(2) subject the two types ofsubstrates 5A and 5B to printing operation.

Specifically, the substrates 5A and 5B are carried into thecorresponding sorting conveyors 41A and 41B of the substrate sorter4A(1) while classified from each other according to a type. Thesubstrate 5 is subjected to printing operation performed by the firstscreen printing section 7A of either the printer 2A(1) or the printer2A(2), and the substrate B is subjected to printing operation performedby the second screen printing section 7B of either the printer 2A(1) orthe printer 2A(2). When the printer 2A(1) is unoccupied, the substrates5A and 5B supplied from the upstream side are carried into the firstscreen printing section 7A and the second screen printing section 7B ofthe printer 2A(1), where the substrates undergo printing operation. Thesubstrates 5A and 5B having undergone printing operation are sent to thesubstrate conveyance sections 8A of the printer 2A(2) by way of thesubstrate sorter 4A(2). Subsequently, the substrates are conveyed towardthe downstream side in a bypassing manner and further sent to the loader3, which is a downstream machine, by way of the substrate sorter 4A(3).

When the printer 2A(1) is in the course of printing operation, thesubstrates 5A and 5B supplied from the upstream side are conveyed to thedownstream side in a bypassing manner by way of the substrate sorter4A(1) and the substrate conveyance section 8A of the printer 2A(1). Thesubstrates are then carried into the first screen printing section 7Aand the second screen printing section 7B of the printer 2A(2) by way ofthe substrate sorter 4A(2), with the result that the substrates undergoprinting operation. The substrates 5A and 5B that have finishedundergoing printing operation are sent to the loader 3, which is adownstream machine, by way of the substrate sorter 4A(3). Specifically,during the substrate conveyance operation, the substrate sorters 4A(2)and (3) act as substrate delivering/receiving sections that deliver orreceive the substrate 5 between the substrate positioning section 21 orthe substrate conveyance section 8 and the downstream machine situatedon the downstream side of the printer 2A.

Detailed substrate conveyance operation is described by reference toFIGS. 11 and 12. First, as shown in FIG. 11( a), the substrate 5A iscarried into the sorting conveyor 41A of the substrate sorter 4A(1), andthe substrate 5B is carried into the sorting conveyor 41B of thesubstrate sorter 4A(1). Next, as shown in FIG. 11( b), the substrate 5Ais carried into the first screen printing section 7A of the printer2A(1), where the substrate undergoes printing operation. The substrate5B is carried into the second screen printing section 7B of the printer2A(1), where the substrate undergoes printing operation. In thesubstrate sorter 4A(1), the sorting conveyors 41A and 41B received newsubstrates 5A and 5B supplied from the upstream side are moved at thistime toward the substrate conveyance section 8A of the printer 2A(1),and the sorting conveyors 41A and 41B are coupled to the substrateconveyance lanes L1 and L2.

As shown in FIG. 11( c), during the course of the substrates 5A and 5Bundergoing printing operation performed by the first screen printingsection 7A and the second screen printing section 7B, the substrates 5Aand 5B are carried in a bypassing manner by way of the substrateconveyance lanes L1 and L2 of the substrate conveyance section 8A. Inthe substrate sorter 4A(2), the substrates 5A and 5B are sent to thesorting conveyors 42A and 42B that have already moved to the locationwhere the sorting conveyors are coupled to the respective substrateconveyance lanes L1 and L2 of the substrate conveyance section 8A. Asshown in FIG. 11( d), the sorting conveyors 42A and 42B received thesubstrates 5A and 5B are moved to the first screen printing section 7Aand the second screen printing section 7B of the printer 2A(2).

Subsequently, as shown in FIG. 12( a), the substrates 5A and 5B arecarried from the sorting conveyors 42A and 42B into the first screenprinting section 7A and the second screen printing section 7B of theprinter 2A(2), where the substrates undergo printing operation. Further,the substrates 5A and 5B that have undergone printing operation in thefirst screen printing section 7A and the second screen printing section7B of the printer 2A(1) are delivered to the sorting conveyors 42A and42B, respectively. Next, as shown in FIG. 12( b), the sorting conveyors42A and 42B received the substrates 5A and 5B move toward the substrateconveyance section 8A of the printer 2A(2), to thus become coupled tothe respective substrate conveyance lanes L1 and L2. At this time, inthe substrate sorter 4A(1), new substrates 5A and 5B are carried intothe sorting conveyors 41A and 41B.

Subsequently, as shown in FIG. 12( c), the substrates 5A and 5B thathave undergone printing operation are sent from the respective sortingconveyors 42A and 42B to the substrate conveyance lanes L1 and L2 of thesubstrate conveyance section 8A of the printer 2A(2), to thus beconveyed to the downstream side in a bypassing manner. Concurrently, newsubstrates 5A and 5B are carried from the respective sorting conveyors41A and 41B into the first screen printing section 7A and the secondscreen printing section 7B of the printer 2A(1), respectively, where thesubstrates undergo printing operation. As shown in FIG. 12( d), thesubstrates 5A and 5B conveyed so as to bypass the substrate conveyancesection 8A of the printer 2A(2) after having undergone printingoperation are sent to the sorting conveyors 43A and 43B of the substratesorter 4A(3) and further to the loader 3A that is a downstream machine.In subsequent operation, analogous substrate conveyance operationintended for the substrate 5A and the substrate 5B are repeatedlyperformed.

Third Embodiment

FIG. 13 is a plan view showing a configuration of an electroniccomponent mounting line of a third embodiment of the present invention,and FIGS. 14, 15, and 16 are descriptive operation diagrams of substrateconveyance motion of a screen printer of the third embodiment of thepresent invention.

First, a configuration of an electronic component mounting line 1B isdescribed by reference to FIG. 13. The electronic component mountingline 1B has a function of manufacturing a mounted substrate by mountingelectronic components on a substrate as does the electronic componentmounting line 1 described in connection with the first embodiment; andis configured in such a way that the screen printer 2A that printselectronic component bonding paste on a substrate is coupled to anupstream side of a loader 3B that mounts electronic components on asubstrate. In the third embodiment, two loaders 3B(1) and 3B(2) arrangedin series are coupled to respective downstream sides of the twoseries-arranged printers 2A as in the case of the second embodiment.

In order to deliver and receive the substrates among the machine, thesubstrate sorter 4A(1) is adjacently disposed on the upstream side ofthe printer 2A(1). The substrate sorter 4A(2) is adjacently interposedbetween the printer 2A(1) and the printer 2A(2). The substrate sorter4A(3) is adjacently disposed on the downstream side of the printer2A(2). The substrate sorters 4A(1) to (3) have the same configuration astheir counterparts described in connection with the second embodiment.The substrates carried out of the upstream machine are carried into theprinter 2A(1) by way of the substrate sorter 4A(1) and further into theprinter 2A(2) by way of the substrate sorter 4A(2). The substrates thathave undergone printing operation in the printer 2A(1) or the printer2A(2) are delivered to the loader 3B(1) by way of the substrate sorter4A(3).

A configuration of the loader 3B is now described. The loader 3B(1) andthe loader 3B(2) assume the same configuration. The loader 3B isdifferent from the loader 3 described in connection with the firstembodiment in that the substrate conveyance path is laid in the centeralong the direction of conveyance of a substrate (the X direction). Inother respects, the loader 3B is structurally identical with the loader3. Specifically, in the loader 3B, there are laid in parallel to eachother four substrate conveyance rails 12A, 12B, 12C, and 12D, each ofwhich has a conveyor mechanism for conveying a substrate. The substrateconveyance rails 12A, 12B, 12C, and 12D make up substrate conveyancelanes L1, L2, L3, and L4 that convey the substrates 5 sent from theupstream side by way of the substrate sorter 4A(3).

In the substrate sorter 4A(3), the sorting conveyors 43A and 43B aremoved, thereby being able to deliver and receive the substrates 5between the substrate conveyance lanes L1, L2, L3, and L4 of the loader3B(1) and the substrate conveyance lanes L1 and L2 of the printer 2A, byway of the sorting conveyors 43A and 43B. Likewise, the sortingconveyors 43A and 43B are moved, whereby the substrates 5 can bedelivered from the respective substrate positioning sections 21 of thefirst screen printing section 7A and the second screen printing section7B of the printer 2A to the substrate conveyance lanes L1, L2, L3, andL4 of the loader 3A. Each of the substrate conveyance lanes L1, L2, L3,and L4 is equipped with the mounting stage where the substrate 5 ispositioned at the mounting position and subjected to mounting operation.The component loading mechanism similar to the loader 3 described inconnection with the first embodiment transfers and mounts electroniccomponents to and on the substrate 5 positioned on the mounting stage.

By reference to FIGS. 14, 15, and 16, substrate conveyance operation ofthe printer 2A making up the electronic component mounting line 1B isnow described. There is illustrated example substrate conveyanceoperation performed when four different types of substrates 5 (thesubstrate 5A, the substrate 5B, the substrate 5C, and the substrate 5C)are concurrently subjected to printing operation. FIG. 14 shows generalwork classification effected when the two printers 2A(1) and 2A(2)subject four types of substrates 5A, 5B, 5C, and 5D to printingoperation.

The four types of substrates 5A, 5B, 5C, and 5D are classified into twogroups. New substrates 5A and 5B that have not yet subjected toprocessing are first carried into the sorting conveyor 41A of thesubstrate sorter 4A(1) and undergo printing operation performed by thefirst screen printing section 7A in either the printer 2A(1) or theprinter 2A(2). Moreover, new substrates 5C and 5D that have not yetsubjected to processing are first carried into the sorting conveyor 41Band undergo printing operation performed by the second screen printingsection 7B in either the printer 2A(1) or the printer 2A(2).Specifically, the first screen printing sections 7A and the secondscreen printing sections 7B of the printers 2A(1) and 2A(2) individuallyperform printing operations intended for different types of substrates.The four types of substrates are thereby subjected to printingconcurrently.

When specific two types of substrates (the substrate 5A and thesubstrate 5C of the embodiment shown in FIG. 14) are objects of printingoperation performed by the first screen printing section 7A and thesecond screen printing section 7B of the printer 2A(1), the substrateconveyance section 8A of the printer 2A(1) conveys the other two typesof substrates (the substrate 5B and the substrate 5D that are objects ofprinting operation performed by the printer 2A(2)) to the downstreamside in a bypassing manner. Likewise, when specific two types ofsubstrates (the substrate 5B and the substrate 5D of the embodimentshown in FIG. 14) are objects of printing operation performed by thefirst screen printing section 7A and the second screen printing section7B of the printer 2A(2), the substrate conveyance section 8A of theprinter 2A(2) conveys the other two types of substrates (the substrate5A and the substrate 5C that have finished undergoing printing operationby means of the printer 2A(1)) to the downstream side in a bypassingmanner. All of the substrates 5A, 5B, 5C, and 5D that have finishedundergoing printing operation are delivered to respective specifiedsubstrate conveyance lanes of the loader 3B(1), which is a downstreammachine, by way of the substrate sorter 4A(3), to thus be conveyed tothe downstream side. In the course of conveyance operation, therespective machines sequentially transfer and mount electroniccomponents on the substrate 5A, the substrate 5B, the substrate 5C, andthe substrate 5D.

Detailed substrate conveyance operation is described by reference toFIGS. 15 and 16. First, as shown in FIG. 15( a), the substrates 5A and5C are carried into the sorting conveyors 41A and 41B of the substratesorter 4A(1). Next, as shown in FIG. 15( b), the substrates 5A and 5Care carried into the first screen printing section 7A and the secondscreen printing section 7B of the printer 2A(1), where the substratesundergo printing operation. In the substrate sorter 4A(1), the sortingconveyors 41A and 41B received new substrates 5B and 5D, which have notyet undergone processing, from an upstream machine move toward thesubstrate conveyance section 8A of the printer 2A(1), thereby couplingthe sorting conveyors 41A and 41B to the substrate conveyance lanes L1and L2, respectively.

During the course of the substrates 5A and 5C undergoing printingoperation in the first screen printing section 7A and the second screenprinting section 7B, the substrates 5B and 5D are carried in a bypassingmanner by way of the substrate conveyance lanes L1 and L2 of thesubstrate conveyance section 8A, as shown in FIG. 15( c). Subsequently,in the substrate sorter 4A(2), the substrates 5B and 5D are sent to thesorting conveyors 42A and 42B that have already moved to the positionwhere the conveyors are coupled to the substrate conveyance lanes L1 andL2 of the substrate conveyance section 8A. Next, as shown in FIG. 15(d), the sorting conveyors 42A and 42B received the substrates 5B and 5Dmove toward the first screen printing section 7A and the second screenprinting section 7B of the printer 2A(2).

Subsequently, as shown in FIG. 16( a), the substrates 5B and 5D arecarried from the respective sorting conveyors 42A and 42B to the firstscreen printing section 7A and the second screen printing section 7B ofthe printer 2A(2), whereupon the substrates undergo printing operation.Concurrently, the substrates 5A and 5C that have finished undergoingprinting operation in the first screen printing section 7A and thesecond screen printing section 7B of the printer 2A(1) are delivered tothe sorting conveyors 42A and 42B. Next, as shown in FIG. 16( b), thesorting conveyors 42A and 42B received the substrates 5A and 5C movetoward the substrate conveyance section 8A of the printer 2A(2), to thusbecome coupled to the substrate conveyance lanes L1 and L2,respectively. At this time, in the substrate sorter 4A(1), newsubstrates 5A and 5C are carried from the upstream machine to thesorting conveyors 41A and 41B.

As shown in FIG. 16( c), the substrates 5A and 5C that have finishedundergoing printing operation are sent from the respective sortingconveyors 42A and 42B to the corresponding substrate conveyance lanes L1and L2 of the substrate conveyance section 8A of the printer 2A(2), tothus be carried to the downstream side in a bypassing manner.Concurrently, new substrates 5A and 5C are carried from the respectivesorting conveyors 41A and 41B into the first screen printing section 7Aand the second screen printing section 7B of the printer 2A(1), wherethe substrates undergo printing operation.

As shown in FIG. 16( d), the substrates 5A and 5C, conveyed so as tobypass the substrate conveyance section 8A of the printer 2A(2) afterhaving finished undergoing printing operation, are sent to thecorresponding sorting conveyors 43A and 43B of the substrate sorter4A(3), to thus be further delivered to respective specific substrateconveyance lanes of the loader 3A(1) that is a downstream machine. Thesubstrates 5B and 5D that have finished undergoing printing operationperformed by the first screen printing section 7A and the second screenprinting section 7B of the printer 2A(2) are sent to the respectivesorting conveyors 43A and 43B of the substrate sorter 4A(3) and likewisesent to respective specific substrate conveyance lanes of the loader3A(1). In subsequent operation, similar substrate conveyance operationintended for the four types of substrates 5A, 5B, 5C, and 5D arerepeatedly performed.

The third embodiment illustrates an example in which the two substrateconveyance lanes L1 and L2 are provided for the respective substrateconveyance sections 8A of the printers 2A(1) and 2A(2). However, threesubstrate conveyance lanes can also be provided in each of the substrateconveyance sections 8A. One of the three substrate conveyance lanes(e.g., the substrate conveyance path located in the center) can becaused to act as a return conveyance path for returning the two types ofsubstrates 5A and 5B, which are turned inside out after having finishedundergoing surface mounting operation, from the downstream side to theupstream side as in the first embodiment. Specifically, in this case,the plurality of substrate conveyance paths provided in the substrateconveyance section 8A assume a form including a return conveyance pathfor conveying a substrate that returns from the downstream side of theelectronic component mounting line to the upstream side of the screenprinter of interest.

In this case, the substrates 5C and 5D described in connection with theexample substrate conveyance operation correspond to the substratesresultant from turning inside out of the substrates 5A and 5B. There isachieved an operation pattern in which four types of printingoperations; namely, printing operations intended for both sides of thetwo types of substrates 5, are performed by the first screen printingsections 7A and the second screen printing sections 7B of the respectiveprinters 2A(1) and 2A(2). In the configuration, the substrate sorter4A(1) and the substrate sorter 4A(2) act as substrate rechargingsections that recharge the substrates returned to the upstream side ofthe screen printer by the return conveyance paths to the substratepositioning section.

As described in connection with the first, second, and thirdembodiments, the screen printer of the present invention has a substrateconveyance section that conveys substrates in the direction ofconveyance of a substrate and that is interposed between two screenprinting sections arranged symmetrically with reference to the centerline of the electronic component mounting line when viewed in plane. Avariety of substrate conveyance forms appropriate for substrateoperation paths in the electronic component mounting line thereby becomepossible.

For instance, as indicated by the example of the first embodiment, thesubstrate conveyance section 8 is used as a return conveyance path thatconveys the substrates which return from the downstream side of theelectronic component mounting line to the upstream side of the screenprinter of interest. When a two-sided mounted substrate is taken as anobject, it thereby becomes possible to perform substrate conveyanceoperation for returning the substrates whose first surface sides havefinished undergoing mounting operation to the upstream side of thescreen printer, by means of the substrate conveyance function of theelectronic component mounting line itself and without use of additionalconveyance means.

Further, the substrate conveyance section 8 is used as a conveyancebypass that conveys to the downstream side the substrates supplied fromthe upstream side of the electronic component mounting line withoutpassing through the screen printing sections of the screen printer ofinterest. In a configuration where a plurality of screen printers arearranged in series, the substrates can thereby be carried into desiredscreen printers at required timings, and the substrates having undergoneprinting can also be carried out of the desired screen printers atrequired timings. Therefore, when compared with the related-art screenprinter in which a substrate is conveyed along a single substrateconveyance path and which has a fixed substrate conveyance sequence, adegree of freedom of substrate conveyance form is significantlyimproved.

Moreover, as described in connection with the second and thirdembodiments, there is provided the substrate conveyance section 8Ahaving the plurality of substrate conveyance lanes, whereby a pluralityof different types of substrates can be subjected to printing operationsperformed by the screen printing sections while concurrently carried,and mixed-flow production involving simultaneous flow of different typesof substrates can be addressed. Incidentally, as previously described,one of the plurality of substrate conveyance lanes is used as a returnconveyance path, whereby a plurality of types of two-sided mountedsubstrates can efficiently be subjected to mounting operation by meansof a single electronic component mounting line.

Although the present invention has been described in detail by referenceto the specific embodiments, it is manifest to those who are skilled inthe art that the invention is susceptible to various alterations ormodifications without departing the spirit and scope of the invention.

The present patent application is based on Japanese Patent Application(JP-A-2008-095614) filed on Apr. 2, 2008 in Japan, the entire subjectmatter of which is incorporated herein by reference.

INDUSTRIAL APPLICABILITY

The screen printer of the present invention yields an advantage of thecapability to concurrently, efficiently subject a plurality ofsubstrates, including different types of substrates, to printingoperation; and is useful in an electronic component mounting field inwhich a mounted substrate is manufactured by mounting electroniccomponents on a substrate.

1. A screen printer system that is coupled to an upstream side of anelectronic component loader which mounts electronic components on asubstrate so as to constitute an electronic component mounting line, andin which two screen printers that print electronic component bondingpaste to the substrate are arranged in series, wherein each of thescreen printers comprises: at least one screen printing section having amask plate formed with a pattern hole and a squeegee moving mechanismletting a squeegee slidably move over the mask plate supplied withpaste; a substrate positioning section that is provided in the screenprinting section and that positions and holds the substrate at a printposition for the screen printing section; and a conveyance bypassarranged in parallel with the screen printing section and lets asubstrate to be sent to a downstream machine pass through; wherein thescreen printer system comprises a substrate sorter provided between thescreen printer situated on an upstream side and the screen printersituated on a downstream side and that sorts a substrate from theconveyance bypass situated on the upstream side to the screen printingsection situated on the downstream side, or sorts a substrate from thescreen printing section situated on the upstream side to the conveyancebypass situated on the downstream side, and wherein the substrate sortersorts the substrate printed by the screen printing section situated onthe upstream side to the conveyance bypass situated on the downstreamside.
 2. A screen printer system that is coupled to an upstream side ofan electronic component loader which mounts electronic components on asubstrate so as to constitute an electronic component mounting line, andin which two screen printers that print electronic component bondingpaste to the substrate are arranged in series, wherein each of thescreen printers comprises: at least one screen printing section having amask plate formed with a pattern hole and a squeegee moving mechanismletting a squeegee slidably move over the mask plate supplied withpaste; a substrate positioning section that is provided in the screenprinting section and that positions and holds the substrate at a printposition for the screen printing section; and a conveyance bypassarranged in parallel with the screen printing section and lets asubstrate to be sent to a downstream machine pass through; wherein thescreen printer system comprises a substrate sorter provided between thescreen printer situated on an upstream side and the screen printersituated on a downstream side and that sorts a substrate from theconveyance bypass situated on the upstream side to the screen printingsection situated on the downstream side, or sorts a substrate from thescreen printing section situated on the upstream side to the conveyancebypass situated on the downstream side, and wherein the substrate sortersorts the substrate conveyed through the conveyance bypass situated onthe upstream side to screen printing section situated on the downstream.3. A screen printing method in a screen printer system that is coupledto an upstream side of an electronic component loader which mountselectronic components on a substrate so as to constitute an electroniccomponent mounting line, and in which two screen printers that printelectronic component bonding paste to the substrate are arranged inseries, wherein each of the screen printers comprises at least onescreen printing section having a mask plate formed with a pattern holeand a squeegee moving mechanism letting a squeegee slidably move overthe mask plate supplied with paste, a substrate positioning section thatis provided in the screen printing section and that positions and holdsthe substrate at a print position for the screen printing section, and aconveyance bypass arranged in parallel with the screen printing sectionand lets a substrate to be sent to a downstream machine pass through,wherein the screen printer system comprises a substrate sorter providedbetween the screen printer situated on an upstream side and the screenprinter situated on a downstream side and that sorts a substrate fromthe conveyance bypass situated on the upstream side to the screenprinting section situated on the downstream side, or sorts a substratefrom the screen printing section situated on the upstream side to theconveyance bypass situated on the downstream side, wherein the screenprinting method comprising a step of sorting a substrate printed by thescreen printing section situated on the upstream side to the conveyancebypass situated on the downstream side by the substrate sorter.
 4. Ascreen printing method in a screen printer system that is coupled to anupstream side of an electronic component loader which mounts electroniccomponents on a substrate so as to constitute an electronic componentmounting line, and in which two screen printers that print electroniccomponent bonding paste to the substrate are arranged in series, whereineach of the screen printers comprises at least one screen printingsection having a mask plate formed with a pattern hole and a squeegeemoving mechanism letting a squeegee slidably move over the mask platesupplied with paste, a substrate positioning section that is provided inthe screen printing section and that positions and holds the substrateat a print position for the screen printing section, and a conveyancebypass arranged in parallel with the screen printing section and lets asubstrate to be sent to a downstream machine pass through, wherein thescreen printer system comprises a substrate sorter provided between thescreen printer situated on an upstream side and the screen printersituated on a downstream side and that sorts a substrate from theconveyance bypass situated on the upstream side to the screen printingsection situated on the downstream side, or sorts a substrate from thescreen printing section situated on the upstream side to the conveyancebypass situated on the downstream side, wherein the method comprises astep of sorting the substrate conveyed through the conveyance bypasssituated on the upstream side to screen printing section situated on thedownstream by the substrate sorter.